Facet patterns and arrangements for gemstones

ABSTRACT

The present invention relates to the cut of a gemstone, and particularly to facet patterns and arrangements for modified round brilliant cut gemstones having fifty-eight facets. In one embodiment, a facet pattern for the crown of a gemstone includes an octagonal facet; a plurality of triangular star facets; a plurality of triangular upper main facets; a plurality of upper girdle facets; a plurality of quadrilaterals lower main facets, a plurality of triangular lower main facets, and a plurality of lower girdle facets. Both the lower and upper girdle facets have at least one scalloped edge.

BACKGROUND

1. Field of the Invention

The present invention relates to the cut of a gemstone, particularly to facet patterns and arrangements for diamonds.

2. Background of the Invention

Cut, color, clarity, and carat weight are among several factors considered in determining the value of a gemstone. Cut, however, is considered among many the essential characteristic in assessing a gemstone's beauty. Cut is the only human contribution to a gemstone's beauty and refers to numerous aspects of lapidary craftsmanship, including, but not limited to, a gemstone's overall proportions, facet pattern and arrangement.

Because of their unique optical properties, diamonds, in particular, are very desirable to consumers. To assess the quality of a diamond's cut, four characteristics are typically graded: brilliance, external symmetry, optical symmetry, and polish. Those in the art also consider other properties, including dispersion, fire, and scintillation, in assessing a diamond's beauty. With respect to cut, however, improvements in brilliance and symmetry are very critical.

Brilliance, also referred to as optical brilliance, refers to the quantifiable return of light as seen from a person viewing the diamond. Specifically, this refers to the amount of light that is reflected back to the viewer from the arrangement of facets. The facet pattern and arrangement of a traditional brilliant cut diamond is designed for exceptional brilliance.

The traditional brilliant cut is round with a total of fifty-eight facets. Thirty-three facets are on the crown, the upper section of the diamond, and twenty-five facets are on the pavilion, the lower section of the diamond. The crown and pavilion are separated by a narrow section called the girdle.

The girdle of a standard round brilliant diamond is scalloped and consists of forty-eight different areas around the diamond's outer periphery that correspond to the areas where girdle thickness is measured. These areas are known in the art as girdle valleys, girdles halves, and girdle bezels. However, these areas are typically not included in the total facet count for the diamond.

The girdle of a gemstone can have three different types of finishes. Primarily, gemstones are provided with a polished girdle. A polished girdle is one that has a series small, flat polished surfaces that provide additional luster. Alternatively, a girdle may also be left in a rough, unfinished state. When left in this state, the girdle has a frosted appearance. Additionally, a “spit shine” finish, as understood in the art, may be used.

Traditionally, the crown includes a table facet, in the shape of an octagon, disposed primarily in the horizontal plane on top of the crown. Additional facets are provided on a diagonally extending side of the crown. These facets include triangular star facets, quadrilateral upper main facets, left-side upper girdle facets (each having a pointed end directed to the left side), and right-side upper girdle facets (each having a pointed end directed to the right side). The crown generally has eight star facets, eight upper main facets, eight left-side upper girdle facets and eight right-side upper girdle facets. Accordingly, the crown has a total of thirty-three (33) facets.

The pavilion, the lower section of the traditional cut diamond, includes facets on a diagonally extending side of the pavilion. These facets include quadrilateral lower main facets, triangular left-side lower girdle facets (disposed on the left side of the lower main facet), and triangular right-side lower girdle facets (disposed on the right side of the lower main facet). The pavilion generally has eight left-side lower girdle facets, eight right-side lower girdle facets, and eight lower main facets. Optionally, a culet facet is cut into the pavilion on a horizontal plane, which is optimally parallel to the table. Accordingly, including the culet, the pavilion has a total of twenty-five (25) facets.

In the traditional brilliant cut, when light enters the diamond through the crown, it hits one side of the pavilion, bounces to the opposite side, and is then reflected back through the crown to the viewer. To achieve this interaction of light, all facets in the brilliant cut must be set precisely. This precision, or lack thereof, directly affects the quantification of brilliance, which is typically analyzed by exposing the gemstone to a specific lighting environment. The lighting environment, in turn, creates a measurable contrast between the bright and dark areas within the gemstone. In one type of analysis, a photograph is taken of a diamond in an environment that shows areas of light return as white and areas of light leakage as blue.

Both external and optical symmetry are also considered critical to a diamond's overall beauty, particularly with respect to a gemstone's facet pattern and arrangement. External symmetry refers to the physical symmetry of individual facets. In contrast, optical symmetry refers to the consistency of angles between the facets and overall facet alignment. Symmetrical gemstones, and particularly diamonds, reflect light from one facet to another, while at the same time preventing the leakage of light. Irregularities in facet pattern and arrangement can, therefore, negatively impact the quality and beauty of a gemstone. Proportions are critical to the attractiveness of the cut. The relationships between the sizes and angles of the various parts and facets must successfully combine to optimally display brilliance and other important elements of a diamond's visual appeal.

While traditional brilliant cut gemstones are satisfactory for some consumers, other consumers desire gemstones, and specifically diamonds, with improved symmetry and brilliance. To this end, some gemstones cuts are known to have more facets than traditional brilliant cuts in combination with complex facet patterns and arrangements. Due to cost incentives within the jewelry industry, however, these types of cuts are often impractical.

Moreover, for these types of gemstones it is difficult to optimize carat weight, while at the same time enhancing brilliance and retaining gemstone quality. Therefore, in an effort to satisfy consumers and improve costs, there is a need for gemstone cuts with facet patterns and arrangements that optimize carat weight, while simultaneously enhancing a gemstone's beauty through improved symmetry and brilliance.

SUMMARY

In accordance with the invention, improved symmetry and brilliance are achieved by providing gemstones with unique facet patterns and arrangements.

In a first embodiment, a facet pattern for the crown of a gemstone includes an octagonal table facet; a plurality of triangular star facets; a plurality of triangular upper main facets; and a plurality of upper girdle facets. Each upper girdle facet preferably has four edges. In addition, the upper girdle includes at least one scalloped edge, allowing for enhanced brilliance.

In a second embodiment, a facet pattern for the pavilion of a gemstone includes a plurality of quadrilateral lower main facets, a plurality of triangular left-sided lower main facets, a plurality of right-sided lower main facets, and a plurality of lower girdle facets. Each lower girdle preferably has three edges and includes at least one scalloped edge, allowing for enhanced brilliance.

In a third embodiment, a facet pattern and arrangement includes an octagonal facet; a first plurality of triangular facets; a second plurality of triangular facets; and a plurality of lower girdle facets with four edges, wherein at least one edge is scalloped. The facet pattern and arrangement can also include a plurality of quadrilateral facets, a plurality of triangular facets, and a plurality of facets with three edges, wherein at least one edge is scalloped.

A fourth embodiment includes a gemstone having a crown, a pavilion, and a girdle. To assure the optimal use of light, the gemstone has fifty-eight facets. The crown can include an octagonal table facet and a plurality of star facets. Unlike the traditional brilliant cut, however, the gemstone in this embodiment includes a plurality of upper girdle facets with four edges, wherein at least one edge is scalloped, and a plurality of triangular upper main facets. Also, in contrast to the traditional brilliant cut, the crown of the gemstone preferably has twenty-five facets and the pavilion has thirty-three facets.

Moreover, the pavilion, in this embodiment, can include a plurality of quadrilateral lower main facets, a plurality of triangular left-sided lower main facets, a plurality of triangular right-sided lower main facets, and a plurality of lower girdle facets. Also, the lower girdle preferably has three edges, where at least one edge is scalloped, thus allowing for enhanced brilliance.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure. In the drawings:

FIG. 1 a is side view of a gemstone, in accordance with the invention;

FIG. 1 b is a top view of the gemstone, shown in FIG. 1 a;

FIG. 1 c is a bottom view of a gemstone shown in FIG. 1 a;

FIG. 2 a is a side view of a traditional brilliant cut gemstone;

FIG. 2 b is a top view of the traditional brilliant cut gemstone, shown in FIG. 2 a; and

FIG. 2 c is a bottom view of the traditional brilliant cut gemstone, shown in FIG. 2 a;

DETAILED DESCRIPTION

FIG. 1 a is a side view of a gemstone 10, according to one embodiment. The gemstone 10 includes three sections, a crown 12, the upper section; a pavilion 14, the lower section; and a girdle 16, the section between the crown and pavilion. The crown 12 is disposed on the top of the crown 12 in a horizontal plane. Both the crown 12 and pavilion 14 include a plurality of facets, as further described below.

FIG. 1 b is a top view of the gemstone 10, displaying the upper section of the gemstone—the crown 12. As shown, the crown 12 can include a table facet 18 and other facets, having a symmetrical arrangement that is preferably 8-fold. These other facets can include: star facets 20, upper main facets 22, and upper girdle facets 24. Preferably, the crown 12 includes at least eight triangular star facets, at least eight triangular upper main facets, and at least eight upper girdle facets. An upper girdle facet 24 preferably has one boundary line 23 in common with the upper main facets 22. Additionally, an upper main facet 22 preferably has boundary lines 21 in common with star facets 22.

In contrast to the traditional diamond cut, the upper main facets and upper girdle facets are unique. The upper main facets have three edges (22 a, 22 b, and 22 c) and the upper girdle facets have four edges (24 a, 24 b, 24 c, and 24 d). Additionally, the upper girdle facets can include at least one scalloped edge (24 d). Here, scalloped edge means that the edge is rounded. Optionally, the upper girdle facets can include four straight edges, forming a quadrilateral. Where straight edges are included, preferably, these four edges form a trapezoidal shape.

FIG. 1 c is a bottom view of the gemstone 10, displaying the lower portion of the gemstone—the pavilion 14. As shown, the pavilion 14 can include a plurality of lower main facets 28 shaped as quadrilaterals, a plurality of triangular left-side lower main facets 30 a (positioned on the left-side of the quadrilateral lower main facet), a plurality of triangular right-side lower main facets 30 b (positioned on the right-side of the quadrilateral lower main facet) and a plurality of lower girdle facets 32.

The lower main facets and lower girdle facets, within the scope of the invention, are unique. In contrast to the traditional brilliant cut, three sets of lower main facets are provided. In addition, the lower girdle facets have three edges (32 a, 32 b, and 32 c), with two edges of equal length (32 a, 32 b). Additionally, the lower girdle facets can include at least one scalloped edge (32 c).

Optimally, the pavilion 14 of the gemstone 10 includes at least eight lower main facets in the shape of quadrilaterals, at least eight triangular left-side lower main facets 30 a, at least eight triangular right-side lower main facets 30 b, and at least eight lower girdle facets 32, wherein at least one lower girdle facet edge is scalloped. Additionally, each lower girdle facet preferably shares two boundary lines 31 with two triangular lower main facets 30. Two triangular lower main facets 30 also share a boundary line 29 with two lower main facets 28. Optionally, the pavilion can also include a culet facet ranging, as understood in the art, from small to medium.

For comparison purposes, FIGS. 2 a-2 c show a traditional round brilliant cut gemstone 100. FIG. 2 a is a side view of the traditional brilliant cut 100, FIG. 2 b is a top view of the traditional brilliant cut, showing a crown 112, and FIG. 2 c is a bottom view of the traditional round brilliant cut 100, showing a pavilion 122. In FIG. 2 a, the girdle 113 is also shown. Generally, three areas of the girdle are known in the art—the girdle valley 113 a, the girdle half 113 b, and the girdle bezel 113 c.

The crown 112 has a total of thirty-three facets. These facets include one table facet 114, eight star facets 116, eight upper main facets 118 (also known in the art as kite or bezel facets), and sixteen upper girdle facets 120. FIG. 2 c is a bottom view of the traditional round brilliant cut 100, showing pavilion 122. As shown, the pavilion 122 includes a total of 25 facets. These facets include eight lower main facets 124, sixteen lower girdle facets 126, and an optional culet facet 128.

With respect to the overall dimensions of the gemstone 10, however, the following proportions, expressed as a percentage of the girdle diameter, are preferable: a total height of 62%, a table of 56-58%, a crown of 11-13.5%, girdle bezels of 5-7%, girdle halves of 5.6-8.5%, and a pavilion of 41.3-43.3%. In addition, a pavilion angle of 40.1-40.9 degrees is preferable. These proportions contribute to enhanced brilliance and symmetry for embodiments of gemstones within the scope of the invention.

Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the claims. 

1. A facet pattern and arrangement for a crown of a gemstone comprising: an octagonal facet; a first plurality of triangular facets; a second plurality of triangular facets; and a plurality of upper girdle facets having four upper girdle facet edges.
 2. The facet pattern and arrangement of claim 1, wherein the octagonal facet is a table facet.
 3. The facet pattern and arrangement of claim 1, wherein the first plurality of triangular facets is star facets.
 4. The facet pattern and arrangement of claim 1, wherein the second plurality of triangular facets is upper main facets.
 5. The facet pattern and arrangement of claim 1, wherein at least one upper girdle facet edge is scalloped.
 6. The facet pattern and arrangement of claim 1, wherein the facet pattern and arrangement has twenty-five facets.
 7. The facet pattern and arrangement of claim 1, wherein the second plurality of triangular facets has eight facets.
 8. The facet pattern and arrangement of claim 1, wherein the plurality of upper girdle facets has eight facets.
 9. The facet pattern and arrangement of claim 1, wherein the upper girdle facet edges form a trapezoid.
 10. A facet pattern and arrangement for a pavilion of a gemstone comprising: a plurality of quadrilaterals facets, a first plurality of triangular facets, a second plurality of triangular facets, and a plurality of lower girdle facets having three lower girdle facet edges.
 11. The facet pattern and arrangement of claim 10, wherein at least one of the lower girdle facet edges is scalloped.
 12. The facet pattern and arrangement of claim 10, wherein two lower girdle facet edges have substantially equal length.
 13. The facet pattern and arrangement of claim 10, wherein the plurality of quadrilaterals facets has eight facets.
 14. The facet pattern and arrangement of claim 10, wherein the first plurality of triangular facets has eight facets.
 15. The facet pattern and arrangement of claim 10, wherein the second plurality of triangular facets has eight facets.
 16. The facet pattern and arrangement of claim 10, wherein the plurality of lower girdle facets has eight facets.
 17. The facet pattern and arrangement of claim 10, further comprising a culet facet.
 18. The facet pattern and arrangement of claim 17, wherein the facet pattern and arrangement has thirty-three facets.
 19. A facet pattern and arrangement for a gemstone comprising: an octagonal table facet; a plurality of triangular star facets; a plurality of upper main facets; a plurality of upper girdle facets having four upper girdle facet edges; a plurality of quadrilateral lower main facets; a plurality of left-sided lower main facets; a plurality of right-sided lower main facets; a plurality of lower girdle facets; and a culet facet.
 20. The facet pattern and arrangement of claim 19, wherein each upper main facet has three upper main facet edges.
 21. The facet pattern and arrangement of claim 20, wherein at least one upper girdle facet edge is scalloped.
 22. The facet pattern and arrangement of claim 19, wherein each lower girdle facet has at least three edges.
 23. The facet pattern and arrangement of claim 22, wherein at least one lower girdle facet edge is scalloped.
 24. The facet pattern and arrangement of claim 19, wherein the facet pattern and arrangement has fifty-eight facets.
 25. A gemstone comprising: a crown having a plurality of upper girdle facets with four upper girdle facet edges, wherein at least one upper girdle facet edge is scalloped; a pavilion; and a girdle.
 26. The gemstone of claim 25, wherein the gemstone has a plurality of lower girdle facets with three lower girdle facet edges.
 27. The gemstone of claim 26, wherein at least one lower girdle facet edge is scalloped.
 28. The gemstone of claim 26, wherein two lower girdle facets have substantially equal length.
 29. The gemstone of claim 25, further comprising a culet.
 30. The gemstone of claim 29, wherein the gemstone has fifty-eight facets. 